Cement composition



United States Patent ration of New York No Drawing. Continuation ofapplication Ser. No..

83,623, ,Iarr."19;' 1. This application May 19, 1964, Ser. No 1 368,746

' aims. (Cl. 106-57) This application is a continuation of US. SerialNo. 83,623 filed January 19, 1961, now abandoned.

This invention relates to refractory cements and provides cementssuitable for bonding metals, ceramics, and glasses. The cements are alsouseful for making castings, ramming mixes, and efractory bricks. Inaddition, the cements can be used as the Binder component in cermet-typematerials so that the usual sintering is not necessary to effect thebonding. It may also be useful as a binder for thermonuclear elements.

Accorgin to the invent on, the ggrn gnt comppgitiops, lsasaszhmmaaneamnmndsndcahimlet. Erggiursogggrnpoppd, Upon use of the compositionthe zirconium compound or compounds co-act to form a coherent mass,which, if the cement is used as an adsive, adheres to the surfacesjoined thereby.

The WMLEQALMW and p erabl mair euiaanndzaeaeataassd z "ii" c 8fiia'i ta"i another material, eg u oxideormanesium oe m an eeaatm Ht. are: .aaslat ea diaj afiffzhwfifi. stru""'tiii'e'Eli m in tenmgagm rig; izficcug:']l 1us, the matm rmional stead of using a fused materia an admx urg of5;;- coma and tlie other material 933 .usmhjlizei 235M Zirconia iszirconium oxide and zircon is zirconium "cate.

3,285,757 Patented Nov. 15, 1966 As to amounts of materials, one of thezirconium compounds can be wt. percent of the other zirconium compound,and the water soluble silicate, as sodium silicate, can be 8 wt. percentbut preferably at least 25 wt.

5 percent of the combined weights of the zirconium compounds.

The cement composition is used in the wetted form, and whereas theaforementioned proportions of zirconium compounds and sodium silicateare not critical,

10 the proportion of water in the wet composition is important andshould be such that the aqueous medium (which is an aqueous solution ofsodium silicate) contains about 26-32 wt. percent, preferably 30%,sodium silicate.

In the preferred composition, there are 0.5 part zirconia, 0.5 partzircon and about part sodium silicate aqueous solution in which thesodium silicate is about 26 to 32 wt. percent, or better about 30 wt.percent, of the solution.

The class of cements exemplified by those in which the binder precursoris a water soluble silicate are ai J ll i118 and are particularly goodfor joining met s. 0

application following thorough mixing, a thin coating can be applied toeach surface, the pieces can then be brought 25 together 'and the cementallowed to dry. Slow drying is desirable as it avoids bubbling of thecement. Due to porosity. of the materials, drying time will vary. It canbe determined experimentally. Generally, the joint will dry uponovernight standing at room temperature (70 to 90 F.), or at 160 to 170F. for one hour. Either method will yield a joint ready for service atelevated temperatures. The reactions occurring during formation of thejoint or bond may be complete upon the conclusion of either of thementioned procedures, or may be, completed when the bond is for thefirst time heated to elevated temperature. If immediate application of amechanical load is foreseen, a preferred procedure is to subject thebond to either of the two above-mentioned procedures and to then heat itto 1100 F. in 20 minutes.

In one class of the co g g g J H lass ft gggnqs c ghg gpge hop tmgsitiorig 9111211565 stab liz zirconia zircon, and. as the 5 ,co gr s s t a.sflm the lgipder pgecprsor a s h c ate e. w mwm 3 an as t e ndcr recursor a Fspllo compoun. @5 11 n'- sful 1n makm bonds 9mg; These comositions are useful as are *"1'" -m ucts such as castings which uhstandtemperatures positions of the invemww ue 98M excess wherein ternrsinxcess of about 5000 e the cement composition, the zirconia andzircon are so t at 1 "1S part icu-l'arly well suited for use present infine size particle form, and, preferably, one in on in I MM of thesecomponents is relatively coarse and the other is The formulatio he hosrelatively. fine. Desirably, the zirconia is relatively the same inrespc gt to particlesizes relati e p a r ticle c |;v,44n -w:, ue AM -r-z.-. an coarse. The zirconia or stabillzed mule can be 40 sizes andamou t of'the z rrcomyrp ggmpgpn mesh to -325 mesh, and the zircon canbe 200 to set forth above fp rthe compggtQns wllggemijndgp less than 325mesh powder. A stabilized zirconia precursor is sodiu m g The preferredamounts and powder, --80 mesh in admixture with a -325 mesh particu arsizes or the cement compositions for the two zircon powder isparticularly well suited to :the purtypes of binder precursors are thesame. Poses of the inveiltionhe gessa zauasma aisssaasbssaahasaaeteiatheaim zt form 0 phqsp'hori ae gaa iespliir aaadiabiidiide wherein Na O:Si'2 1:3.85.e.g,, 1:3.75 w rel is referred; Y 13--13.6 Wt. rcent f theCOIllbLllQti llQgllig 9f "815 mm preferred amount is 13.3

e composition can be in wet or dry form. In wet form it is an admixtureof powders of the zirconium compounds and an aqueous solution of thewater soluble silicate. In dry form it is an admixture of the ingredients, including sodium silicate which is readily soluble,

in powdered form, and, of course, is wetted with water 6 before beingused.

wt. percent.

Also, the phosphorus compound-containing composition can be wet or dry.When a wet composition, the binder precursor can be aqueous phosphoricacid (orthophosphoric acid) having a P 0 concentration of 0.53 gram/cc.In a dry composition, the phosphorus com- 3 pound can be a decomposablephosphate e g mono- Chemical:

al n l'! Acid resistance:

The pre e osition containing a phosphorus Soluble in HF compound as thebinder precursor is wet, and the wet- Slowly soluble in concentrated H50 (boiling) ting liquid can be any liquid which will serve as a sus- 5Insoluble in HCl, I-INO H PO (H 80 at pending medium for the zirconiumcompound, and which room temp.) will be expelled from the compositionduring curing of Alkali resistance: bonds made therewith. Preferably,the wetting liquid Resistant to boiling KOH (60%) is water. Otherresistance:

A composition found to be well suited for the pur- 19 Resistant to C0, CH at temperatures over poses of the invention comprises about 0.5 .partzirconia 1,800 F. and about 0.5 part zircon and about 0.15 part P 0 theResistant to oxygen and hydrocarbons P 0 being present as aqueousphosphoric acid. The Reacts with carbon at temperatures over 3,000amount of water can be varied over a wide range and F. probably to formcarbides need only be an amount suitable to provide the desiredconsistency.

Example 2Ph0sphorus as binder precursor 'Thecement compositionsexemplified by the cements Parts by wt. containing a phosphorus compoundas a binder precursor St bili d i oni powder, -80 mesh, 35-55% haveexcellent bond strength in refractories, low ther- CaO 0.50 malexpansion and exceptional resistance to heat shock. Milled zircon, -325mesh 0.50

It is therefore well suited as a sealer, mortar, casting compound,surface coating for refractories, slip-type cements and very denseramming and pottery compounds. For application, following mixing, applyto both surfaces and join and then either (a) raise temperaturegradually from room temperature to 2200 F. over a period of at leastabout 60 minutes, or (b) dry at 160 F.- 170 F. for 20-30 minutes, andthen dry by heating from 170 to 1100 F. in 10-20 minutes, and finallycure at 2200 F for 20 minutes.

Instead of using phosphoric acid, there can be used the reaction productof zirconium tetrachloride or zirconium oxychloride and phosphoric acid.Upon con- Phosphoric acid, P 0 equal to 0.53 gram/cc. 0.15

Properties of this cement are substantially the same as those given forthe cement of Example 1 with the following exceptions:

Maximum service temperature, F 5,300

Porosity, percent over 0.2

Alkali resistance Partially resistant to boiling KOH (60%).

In the foregoing examples the analysis for the zirconia and zircon is asfollows:

Stabilized zirconia: Wt., percent tacting these reactants in an aqueousmedium, a precip- ZrO 95.32-93.32 itate forms and this precipitate,following drying, or SiO 0.55 firing at about 2340 F. whereupon an 8%weight loss oc- TiO, 0.66 curs, can be used as the phosphorus compoundwhich Fe O 0.02 is admixed with the zirconium compounds. A1 0 0.02 I 1 d40 CaO 3.52-5.52

Examp 8 1 male as m e! precursor zircon: Wt., percent The formulation isas follows: f a 65-94 Parts by wt. 2 32-65 Stabilized zirconia powder-so mesh, 35-55% 0.29 o 0.50 2 3 Milled zircon, -325 mesh 0.50 5 Sodiumsilicate aqueous solution, Na O:SiO of Alkallne O d S 0.20

1:3.75, at pH 10.0-10.5, B. of 35.0, viscosity of Unless otherwiseindicated, temperatures herein are 220 cps. at 30 C. 0.33

F.; parts are parts by weight; and percent is wt.

percent.

While it is not desired to predicate patentability on any particulartheory, the mechanism whereby bond strength is attained, where thebinder precursor is a Properties of this cement composition followingapplication are as follows:

Thermali, o F 4 300 water soluble silicate, is believed to involve lossof water servlcle f i 3' 5" 5 i by evaporation followed by loss of waterof crystalliza- Cmfi, of henna expanslolz 1 per tion, and then a finalchemical action, at the high tem- Thel'mal g i 9 35 "E pelature, betweenhighly viscous silicate and the zirf con ucnvlty 23 2 conia and zircon.In the case of the compositions of the n t type where the binderprecursor is a phosphorus com- Thel'mal shock reslstance xce en 60pound, the mechanism probably involves the initial loss Mechanical ofsome water so that the phosphoric acid concentra- Hardnss mobs tron 1sincreased, followed by loss of any water of crystal- T t "11 10 00045000 lizations, and finally a chemical reaction of polymeric ens] e 5 fphosphates and phosphoric acids with the zirconium comcompresslvestrength 'P" 80000 ]50000 pounds which occur upon the initial heating tohigh Modulus of rupture p.s.i 23,000 temperature Porosity (refractories,Norton), perw i l i i cent Q02 1. A refractory cement adapted to bemixed with water for use for services involving temperatures in excessof 'Electrlfiali about 4000 F. consisting essentially of particles of aD e ct i e B 200-200 Volts/ In!!- zirconium-containing compositionselected from the group Volume resistivity 1013-1015 OhmS/Cmconsistingof zirconia, zircon and mixtures of the fore Arc resistance Over 500sec. going, and a water-soluble binder precursor selected fromDielectric constant 60 cps. .approx. 9.0; the group consisting of (1) awater-soluble sodium silil0 cps. 7.0-9.0. cate in an amount of at least8% by weight of the zir- 5 6 eonium-containing composition and having anNa O:Si0 one of the zirconium compounds is more finely divided ratio inthe range of 1:3.221:3.85, and (2) a waterthan the Othersolublephosphate compound in an amount equivalent to 13 to 13.6 wt. percent P 0of th zi i i i References Cited by the Examiner composition. 5 UNITEDSTATES PATENTS 5 2. A refractory cement according to claim 1 wherein 109 249 1931 Morgan 10 ....57 the sodium silicate is in the form of anaqueous solution 2,771,37 11 195 Cappenman 10 57 containing 26 to 32 wt.percent sodium silicate. 2,880,097 3/1959 Emhiser 106-454 3. Arefractory cement according to claim 1 wherein 3,138,471 6/1964 Wygant106-84 the zirconium-containing composition is a mixture of zir- 10conia and zircon in a weight ratio of 1:4 to 4:1. TOBIAS LEVOW PnmaryExaminer 4. A refractory cement according to claim 3 wherein POER,Assistant Examiner- M [p r K l/D UNITED STATES PATENT OFFICE CERTIFICATEOF CORRECTION nt Nb 3 285 7-57 November.15, 1966 Kurt W. Cornely errorappears in the above numbered pattifi d that is hereby Ger 9 the saidLetters Patent should read as Equiring correction and that ted below.

Column 3, line 70, for "200-200" read 200-300 Signed and sealed this19th day of September 1967 EDWARD J. BRENNER I I a a Comi mssrener ofPatents T w. SWIDER UNITED STATES PATENT OFFICE CERTIFICATE OFCORRECTION Patent No, 3,285,757 November 15, 1966 Kurt W. Cornely It ishereby certified that error appears in the above numbered patentrequiring correction and that the said letters Patent should read ascorrected below.

Column 3, line 70, for "200-200" read 200-300 Signed and sealed this19th day of September 1967.

(SEAL) Attest:

ERNEST W. SW'IDER EDWARD J. BRENNER Attesting Officer Commissioner ofPatents

1. A REFRACTORY CEMENT ADAPTED TO BE MIXED WITH WATER FOR USE FORSERVICES INVOLVING TEMPERATURES IN EXCESS OF ABOUT 4000*F. CONSISTINGESSENTIALLY OF PARTICLES OF A ZIRCONIUM-CONTAINING COMPOSITION SELECTEDFROM THE GROUP CONSISTING OF ZIRCONIA, ZIRCON AND MIXTURES OF THEFOREGOING, AND A WATER-SOLUBLE BINDER PRECURSOR SELECTED FROM THE GROUPCONSISTING OF (1) A WATER-SOLUBLE SODIUM SILICATE IN AN AMOUNT OF ATLEAST 8% BY WEIGHT OF THE ZIRCONIUM-CONTAINING COMPOSITION AND HAVING ANNA2O:SIO2 RATIO IN THE RANGE OF 1:3.22-1:3.85, AND (2) A WATERSOLUBLEPHOSPHATE COMPOUND IN AN AMOUNT EQUIVALENT TO 13 TO 13.6 WT. PERCENTP2O5 OF THE ZIRCONIUM-CONTAINING COMPOSITION.